1.定義：

例：建一個復(fù)數(shù)類，重載+， -

https://blog.csdn.net/qq_40242197/article/details/118584131

法一：將運(yùn)算符重載作為類函數(shù)

#include<iostream>

#include<cmath>

using namespace std;

class complex {

public:

complex(double r = 0.0,double i=0.0) {

real = r;

imag = i;

}

complex operator +(const complex &c2);

complex operator -(const complex &c2);

void show(){

cout<<"real:"<<real<<" "<<"imag:"<<imag<<endl;

}

double getr() const{//const成員只能調(diào)用const函數(shù)

return real;

}

double geti() const{

return imag;

}

private:

double real;

double imag;

};

complex complex::operator+(const complex &b){

complex d(real+b.getr(),imag+b.geti());

return d;

}

complex complex::operator-(const complex &b){

complex d(real-b.getr(),imag-b.geti());//注意順序不能顛倒?

return d;

}?

int main(){

complex a(1,2),b(3,6),c;

c = a+b;

c.show();

c = a-b;

c.show();

return 0;

}

2.規(guī)則

法二：將運(yùn)算符重載為友元函數(shù)

#include<iostream>

#include<cmath>

using namespace std;

class complex {

public:

complex(double r = 0.0,double i=0.0) {

real = r;

imag = i;

}

void show() {

cout<<"real:"<<real<<" "<<"imag:"<<imag<<endl;

}

private:

double real;

double imag;

friend complex operator +(const complex &c1,const complex &c2);

friend complex operator -(const complex &c1,const complex &c2);

};

complex operator+(const complex &a,const complex &b) {

complex d(a.real+b.real,a.imag+b.imag);

return d;

}

complex operator-(const complex &a,const complex &b) {

complex d(a.real-b.real,a.imag-b.imag);

return d;

}

int main() {

complex a(1,2),b(3,6),c;

c = a+b;

c.show();

c = a-b;

c.show();

return 0;

}